Method of and apparatus for electrically making openings in metal plates.



T. E. MURRAY, In.

METHOD OF AND APPARATUS FOR ELECTRICALLY MAKING OPENINGS IN METAL PLATES. I

APPLICATION FILED JULY 13.12"].

1,242,581. Patented 0% 9,1917.

11 l? W//// ////////////////////,/W// ////A' INIEIIITOR THOHAQI. MURRAY, 173., BROOKLYN, mYOBK.

mon 0] AND APIABATUS FOR ELEOTBIOALLY m6 OPENINGS I! max.

runs.

Specification 0! Letter! Patent.

Patented Oct. 9, 191 '7.

Application fled July 18, 1017. Serial Io. 100,280.

To all whom it may concern:

stbe

. olts J. The cylindrical b ock Be it known that I Tnoms E. Muaaar, Jr., 8. citizen of the llnited States res1d1n5 at Brookl n, in the county of Kmgs an State of ew York, have invented a certain new and useful Improvement in Methods of and Apparatus for Electrically Makin Openings in Metal Plates, of which the 0 lowing 1s a specification.

The invention is a method of and apparatus for electrically making an opemn m a metal plate, without fusing the met of said plate over the whole area of said opening. To this end, I subject an annular portion of said plate to heating by an electric current of sufiicient strength to fuse only said annular ortion, the metal core or portion of the p ate surrounded thereby being thus freed from the remainder of the plate. In this way, I economize in the current required to produce the desired opening because of the comparatively small amount of metal to be melted, and preserve the resultin detached core in what may be a utiliza 1e shapeas, for example, as here shown, in disk form.

In the accompanying drawin Figure 1 is a vertical section of my apparatus on the line 1, 1 of Fig. 2. Fig. 2 is a plan view.

Similar parts.

A is a metal block, having ing B. C is a cylindrica metal bloc of less area than opening 13 and disposed therein, so that an annular interval or gap D surrounds said block C. The metal plate E, in which an openin is to be made, is placed upon the blocks and C so as to cover said p D. Upon plate E is disposed a metal lock F, having an openin similar to opening B, and a cylindrlcal bl bck G, similar to block 0, so that an annular interval or gap H is produced between blocks F and G whlc re ters with gap D.

he blocks A and F maybe secured toether and to an insulatin supgort I by may be pin K. The

letters of reference indicate like a circular 0 ensecured on said support by a cylindrical block G may be hel in place by a bar L of insulating material fastened to block F b screws M. The means for holding the b ocks in place as described, is not esseiggiil, since obvi y other means may One terminal of a circuit may be connected to block F, and the opposite terminal to block G. The blocks A and F, electrically connected through plate E, will, therefore, form one electrode, and the blocks (J and G also electrically connected through opposite terminal. The circuit will then be completed by the annular portion N of plate E which bridges the gaps D and H. The current is to be of such stren h as that said annular portion of plate will become heated and melted sufficiently to flow down into gap D, producing an annular slot in plate E, and so freeing the circular portion of said plate which lies between blocks C and G from the remainder of said plate. In this way, I produce a circular opening in plate E corresponding in area to the openings in blocks A and F.

The disk or core of metal remaining between blocks C and G may be used for any desired purpose.

While I have here shown my invention as applied to the making of a circular opening in the plate, and a circular disk, it will be obvious that I may vary the configuration of said opening by correspondlngl va ing the configuration of the blocks an G and the openings in blocks A and F.

I claim:

1. The method of making an opening of selected configuration through a metal plate, which consists in disposing said plate upon electrodes having an annular gap or interval between them, and melting the portion of the plate bridging said gap, whereby the portion of the plate surrounded by said gap is released from the remainder of said plate.

2. The methodof'separating from a metal plate a portion thereof of selected confi ration, which consists in electrically fusing a narrow annular strip of said plate surrounding the portion to be separated and thereby se arating said portion from the remainder 0 said plate.

3. An apparatus for electrically making an opening through a metal plate, comprising an electrode having an opening, and an electrode of less area disposed within said opening so that an annular gap or interval is produced between said electrodes, the said plate being in contact with said electrodes and covering said 'ga 4-. An apparatus or electrically making an opening through a metal plate, comprisplate, will form the ing an electrode formed in two parts receivbetween said electrodes and respectively on 0 ing the plate between them and having regop osite sides of said plate. istering openings, and a second electrode 11 testimony whereof I have aifi zed my formed in two parts receiving the plate besignature in presence of two witnesses. 5 tween them, the sand parts bein respectively disposed in the opemngs of sai first-named THOMAS MURRAY parts, the parts of the second electrode be- Witnesses: mg of less area than the parts of the first Gnn'mmm T. PORTER,

electrode so that annular gaps are formed MAY T. MGGARRY. 

